By default, DDLs are ‘owned’ by the user. The lists are stored on the local computer by default. Only by mirroring two installations will DDLs be shared. (Mirroring is applicable to network installs only, of course).
However, when Pathagoras is installed in a 'terminal server' environment, the opposite condition exists. In that environment, there is a single ‘Pathagoras’ folder and as a consequence, the DDL are shared by default. For many with such 'terminal server' installs, that is the preferred setup, so we have left it as the default.
But when it isn’t the desired setup, reverting to individual DDLs is just a flip of a switch. Simply navigate to 'Pathagoras Features (bottom half) | DropDown Lists | DDL Tools | Special Situations'. Check the 'Use separate users settings' and each user can now create personal DropDown Lists.